Bidirectional relationship between olfaction and Parkinson's disease

Background

Hyposmia (loss of smell) is a common early symptom of Parkinson's disease (PD). The shared genetic architecture between hyposmia and PD is unknown.

Methods

We leveraged genome-wide association study (GWAS) results for self-assessment of 'ability to smell' and PD diagnosis. Linkage disequilibrium score regression (LDSC) and Local Analysis of [co]Variant Association (LAVA) were used to identify genome-wide and local genetic correlations. Mendelian randomization was used to identify potential causal relationships.

Results

LDSC found that sense of smell negatively correlated at a genome-wide level with PD. LAVA found negative correlations in four genetic loci near GBA1, ANAPC4, SNCA, and MAPT. Using Mendelian randomization we found evidence for strong causal relationship between PD and liability towards poorer sense of smell, but weaker evidence for the reverse direction.

Conclusions

Hyposmia and PD share genetic liability in only a subset of the major PD risk genes. While there was definitive evidence that PD can lower the sense of smell, there was only suggestive evidence for the reverse. This work highlights the heritability of olfactory function and its relationship with PD heritability and provides further insight into the association between PD and hyposmia.

Neurological Manifestation in Hospitalized Patients With Acute SARS-CoV-2 Infection

OBJECTIVE

The main objective of this research is to determine the prevalence and characteristics of neurological manifestations in hospitalized patients with SARS-CoV-2 infection.

METHODS

A cross-sectional study was conducted. 572 hospitalized patients at the COVID Department of Pulmonology of the Mostar University Clinical Hospital in the six-month period from October 31, 2020, to April 30, 2021, were included. We analyzed the incidence of neurological manifestations and the influence of comorbidities and metabolic syndrome on stroke incidence in COVID-19 patients. We analyzed hospital length of stay and mortality in patients with and without neurological manifestations. The research was conducted with respect to all the determinants of the Helsinki Declaration.

RESULTS

572 patients, 351 men (61.4%), and 221 women (38.6%) were included. A fatal outcome was present in a quarter of patients (25.3%). Neurological manifestations were found in 163 patients (28.5%). Myalgia was the most common (16.1%). The following were reported: headache (9.6%), loss of taste (7.34%), loss of smell (6.8%), and vertigo (2.5%). There was a significant difference regarding loss of smell between males and females (p=0.04). The cerebrovascular incident was present in 2.97% of patients and was more frequent in the group of patients with metabolic syndrome. Patients with neurological manifestations had a longer hospital stay, but it was not statistically significant (p=0.9319). The presence of neurological manifestations in general did not influence the mortality rate.

CONCLUSION

Patients with SARS-CoV-2 infection can present with neurologic findings such as myalgia, headache, loss of smell or taste, vertigo, as well as cerebrovascular incidents. Patients with neurological manifestations had longer hospital stays, but the presence of neurological manifestations in general did not influence the mortality rate.

Efficacy of Stellate Ganglion Block in Treating Long-Term COVID-19-Related Olfactory and Gustatory Dysfunction: A Case Series

Olfactory and gustatory dysfunction, including anosmia, parosmia, ageusia, and dysgeusia, are common long-term symptoms of coronavirus disease 2019 (COVID-19) infection. These symptoms can have a severe impact on quality of life of a patient, including psychological well-being. Stellate ganglion block (SGB) has recently been explored as a potential therapeutic intervention for these symptoms. In this case series, we present six patients with long-term COVID-19 symptoms and we detail how their symptoms evolved after an SGB. All SGB were performed under ultrasound guidance by the same physician. Patients had a right SGB during the initial visit, followed by a left SGB at a subsequent visit. All but one patient reported improvements in olfaction and gustation after the SGB. Our findings suggest that SGB may be a promising therapeutic intervention for patients with olfactory and gustatory dysfunction related to long-term COVID-19 symptoms. Further research is needed to confirm these findings and to explore the optimal treatment protocol.

Olfactory and Gustatory Dysfunctions Following COVID-19 Infection: Factors That Affect Their Duration in Saudi Arabia

INTRODUCTION

 Many people infected with coronavirus disease 2019 (COVID-19) have developed post-COVID-19 symptoms, which are defined as symptoms and signs (e.g., anosmia and ageusia) that persist for more than 12 weeks after getting infected with COVID-19. These symptoms may appear after or during the infection and cannot be explained by any alternative disease. In this study, we aim to investigate the factors that affect the duration of anosmia and ageusia in Saudi Arabia.

METHODS

 We conducted a nationwide, cross-sectional study using an online survey in Saudi Arabia from 14 February 2022 to 23 July 2022. The electronic survey was distributed using social media platforms, such as Twitter, WhatsApp, and Telegram.

RESULT

 The study enrolled 2497 individuals who were infected with COVID-19. A total of 60.1% of the participants showed symptoms of anosmia, ageusia, or both after getting infected with COVID-19. According to our data, we found that being a female and not having a repeated COVID-19 infection were risk factors (independent predictors) of the long duration of anosmia after COVID-19 recovery (p = <0.05). While being a male patient, a smoker, and being admitted to the ICU were risk factors (independent predictors) of long duration of ageusia after COVID-19 recovery (p = <0.05).

CONCLUSION

 In conclusion, the prevalence of chemosensory dysfunction symptoms, both olfactory and gustatory, after COVID-19 infection among the Saudi population was high. However, several factors can influence their duration, including gender, smoking, and severity of the infection.

Treatment of Olfactory Disorders After SARS - CoViD 2 Virus Infection

OBJECTIVE

The benefit of a nasal corticosteroid in the treatment of persistent post-infectious smell disorders is not as clear in previous studies as is assumed for olfactory training. This study would therefore like to describe the treatment strategies using the example of a persistent olfactory dysfunction as a result of a proven infection with SARS-CoViD-2-virus.

METHODS

Twenty patients (average age of 33.9 ± 11.9 years) with hyposmia were included in this study from December 2020 to July 2021. Every second patient received additionally a nasal corticosteroid. The two resulting randomized groups of equal size were screened with the TDI test, a 20-item taste powder test for the assessment of retronasal olfaction and otorhinolaryngological examination. The patients were asked to train twice daily using a standardized odor training kit and followed up after 2 months and 3 months, respectively.

RESULTS

We documented a significant overall improvement in olfactory ability over the investigation period in both groups. While the TDI score steadily increased on average under the combination therapy, the rise under olfactory training alone was initially steeper. This short-term interaction effect over mean two months was not statistically significant. According to Cohen, however, a moderate effect (eta2 = 0.055, Cohen`s d = 0.5) can still be assumed. This effect could be explained by a possibly higher compliance at the beginning of the sole olfactory training due to the lack of further drug treatment offers. When the training intensity decreases, the recovery of the sense of smell stagnates. Adjunctive therapy ultimately outweighs this short-term benefit.

CONCLUSIONS

The results reinforce the recommendation of early and consistent olfactory training on patients with dysosmia due to COVID-19. For continuous improvement of the sense of smell, an accompanying topical treatment seems at least to be worth consideration. The results should be optimized with larger cohorts and using new objective olfactometric methods.

Doxycycline Improves Quality of Life and Anosmia in Chronic Rhinosinusitis With Nasal Polyposis: A Randomized Controlled Trial

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex disorder and effective treatment remains a major challenge. Some antibiotics with anti-inflammatory properties are reported to have potential to be used as an adjunct therapy in the management of chronic airway inflammation.

OBJECTIVE

The aim of this study was to evaluate the efficacy of doxycycline in CRSwNP.

METHODS

In this randomized, double-blind, placebo-control study, we assessed the efficacy of doxycycline in patients with moderate to severe CRSwNP. A total of 100 patients were randomly assigned to receive either doxycycline (200 mg on the first day followed by 100 mg daily) or placebo for 6 weeks. All patients received baseline therapy with fluticasone, montelukast, and nasal irrigation during the study. The primary outcome was quality of life based on the sino-nasal outcome test (SNOT-22) questionnaire. We measured peak nasal inspiratory flow (PNIF) and severity of symptoms by visual analogue scale (VAS). Baseline blood eosinophil count, serum IgE level, eosinophil in nasal secretions, and Lund-Mackay score based on low dose paranasal CT scan were also recorded.

RESULTS

Treatment with doxycycline significantly improved SNOT-22 (P = .037) and sense of smell (P = .048). The baseline SNOT-22 score had no effect on outcomes. The effect of doxycycline on quality of life in patients with or without nasal eosinophilia was not significantly different. Change in SNOT-22 score was also not correlated with serum IgE (P = .220, r = -0.186) and the eosinophil count (P = .190, r = -0.198).

CONCLUSION

Doxycycline improves the quality of life in patients with CRSwNP. It also has temporarily beneficial effects in improving the sense of smell. The levels of eosinophil in the blood and nasal secretions do not affect the response to treatment. Hence, doxycycline can be used in both eosinophilic and non-eosinophilic nasal polyps.This study was registered at Iranian Registry of Clinical Trials. https://www.irct.ir/ IRCTID: IRCT20210403050817N1.

Visual Analog Scale and Olfactory Objective Tests in Hyposmia Patients: Is There a Link?

Introduction Olfactory dysfunction (OD) is often a devaluated sensorial affection. The objective evaluation of this dysfunction does not evaluate its compromise in patients' daily life. It is unclear to what extent there is a correlation between the objective evaluation of OD and patient-reported impairment. Objective We aim to search if Sniffin Sticks® correlates with the Visual Analog Scale (VAS) of Hyposmia Symptoms, and therefore if it is a useful method for clinical use. Methods A prospective study was carried out to evaluate and compare consecutive patients who had olfactory impairment due to COVID-19 that were referred to an otolaryngology office. The variables evaluated were gender, age, co-morbidities, and olfactory thresholds (measured according to Sniffin Sticks®). Patients were also enquired about their sense of impairment according to VAS from 1 (worst possible) to 10 (best possible). Statistical analysis was performed using SPSS (IBM SPSS Statistics 26). Normal distribution was checked using both skewness and kurtosis and Kolmogorov-Smirnov tests. Pearson correlation test was used to seek a correlation between VAS and olfactory thresholds. All reported p-values are two-tailed, with a p-value ≤ 0.05 indicating statistical significance. Results Our sample of 47 patients was composed of 30 females (63.8%) and 17 females (36.2%). We found a mean variation between olfactory thresholds before and after the intervention of 3.91±2.466, and an average improvement of 2.29±2.93 in the visual analog scale for subjective evaluation of olfactory impairment. According to the Pearson correlation test, with 95% confidence, there is evidence to claim a moderate association (0.512) between an improvement in olfactory thresholds and VAS (p=0.05). Conclusions There was a moderate correlation between ratings and measures of olfactory function. On an individual basis, there were remarkable differences between measures and ratings of olfactory function. VAS should be considered in the evaluation of the hyposmic patient, due to its simplicity and quick applicability.

Prevalence of Olfactory Dysfunction with the Omicron Variant of SARS-CoV-2: A Systematic Review and Meta-Analysis

The omicron variant is thought to cause less olfactory dysfunction than previous variants of SARS-CoV-2, but the reported prevalence differs greatly between populations and studies. Our systematic review and meta-analysis provide information regarding regional differences in prevalence as well as an estimate of the global prevalence of olfactory dysfunction based on 62 studies reporting information on 626,035 patients infected with the omicron variant. Our estimate of the omicron-induced prevalence of olfactory dysfunction in populations of European ancestry is 11.7%, while it is significantly lower in all other populations, ranging between 1.9% and 4.9%. When ethnic differences and population sizes are considered, the global prevalence of omicron-induced olfactory dysfunction in adults is estimated to be 3.7%. Omicron's effect on olfaction is twofold to tenfold lower than that of the alpha or delta variants according to previous meta-analyses and our analysis of studies that directly compared the prevalence of olfactory dysfunction between omicron and previous variants. The profile of the prevalence differences between ethnicities mirrors the results of a recent genome-wide association study that connected a gene locus encoding an odorant-metabolizing enzyme, UDP glycosyltransferase, to the extent of COVID-19-related loss of smell. Our analysis is consistent with the hypothesis that this enzyme contributes to the observed population differences.

Prevalence of Olfactory Dysfunction with the Omicron Variant of SARS-CoV-2: A Systematic Review and Meta-analysis

The omicron variant is thought to cause less olfactory dysfunction than previous variants of SARS-CoV-2, but the reported prevalence differs greatly between populations and studies. Our systematic review and meta-analysis provide information about regional differences in prevalence as well as an estimate of the global prevalence of olfactory dysfunction based on 62 studies reporting on 626,035 patients infected with the omicron variant. Our estimate of the omicron-induced prevalence of olfactory dysfunction in populations of European ancestry is 11.7%, while it is significantly lower in all other populations, ranging between 1.9% and 4.9%. When ethnic differences and population sizes are taken into account, the global prevalence of omicron-induced olfactory dysfunction in adults is estimated at 3.7%. Omicron’s effect on olfaction is twofold to tenfold lower than that of the alpha or delta variant, according to previous meta-analyses and our analysis of studies that directly compared prevalence of olfactory dysfunction between omicron and previous variants. The profile of prevalence differences between ethnicities mirrors the results of a recent genome-wide association study that implicated a gene locus encoding an odorant-metabolizing enzyme, UDP glycosyltransferase, to be linked to the extent of COVID-related loss of smell. Our analysis is consistent with the hypothesis that this enzyme contributes to the observed population differences.

Why Does the Omicron Variant Largely Spare Olfactory Function? Implications for the Pathogenesis of Anosmia in Coronavirus Disease 2019

The omicron variant of severe acute respiratory syndrome coronavirus 2 causes much less olfactory dysfunction than the previous variants. There are several potential mechanisms for how omicron may change tissue tropism and spare olfactory function. The new mutations make omicron more hydrophobic and alkaline than previous variants, which may reduce penetration of the mucus layer. Overall, the new mutations minimally change receptor binding affinity, but entry efficiency into host cells is reduced in cells expressing transmembrane serine protease 2 (TMPRSS2). Because the support cells in the olfactory epithelium abundantly express TMPRSS2, these main target cells in the olfactory epithelium may become infected less by the new omicron variant.

COVID-19 loss of taste and smell: potential psychological repercussions

The novel coronavirus (COVID-19) has become a cause for global concern. Apart from a multitude of symptoms, the virus is known for its ability to cause loss of taste and smell that can be irreversible in a few cases. In fact, even after recovery, post-covid syndrome can still lead to devastating outcomes, specifically with reference to loss of smell and taste. A number of mechanisms that have been postulated include receptor-mediated uptake, increased inflammation, transneuronal migration, and direct damage to the olfactory pathway. Considering how important these two senses are, many psychological, social, and emotional repercussions can be expected. These repercussions include lowering of self-esteem and developmental of mental health issues. Long-term altered taste sensation can also lead to the development of unhealthy eating habits that can result in increasing risk for diabetes and hypertension. A few solutions have been investigated for treating these chemosensory dysfunctions, such as olfactory training, corticosteroids, theophylline and acupuncture. Although the results have been promising but a new modality, virtual reality, requires more in-depth exploration because it targets not only the dysfunction but also the mental health issues being experienced. It is important that affected individuals be provided with strong emotional and family support. Additionally, physicians can help the patients through support groups, cognitive behavioural therapy, olfactory, and virtual reality training.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

COVID-19-Associated Parosmia and Dysgeusia: A Case Series

Impairment of the chemical senses - smell, taste, and chemesthesis - has been pinpointed as one of the main clinical presentations of coronavirus disease 2019 (COVID-19). Chemosensory dysfunction can be quantitative, involving reduction or loss of perception (e.g., hyposmia, anosmia, hypogeusia), and qualitative, involving distortion of perception (parosmia and dysgeusia). Quantitative chemosensory dysfunction is reported more often among COVID-19 patients than qualitative dysfunction. The following report details four patients with a laboratory-assisted diagnosis of COVID-19 who experienced qualitative chemosensory dysfunction. A discussion of these symptoms in the broader context of upper respiratory tract infections is included, with an emphasis on olfactory dysfunction.

Long-Term Neurological Impact of COVID-19

INTRODUCTION

Recent research has observed the ability of coronavirus disease 2019 (COVID-19) to spread in the brain from the respiratory system. The associated neurological disorder includes encephalopathies, inflammatory syndromes, stroke, peripheral neuropathies, and various other central nervous system disorders. This study aims to highlight the long-term neurological sequelae in patients with COVID-19 disease.

METHODS

This long-term study was carried out in the COVID-19 unit of a tertiary care hospital in Pakistan from July 2020 to July 2021. After obtaining informed consent, we enrolled 1000 patients who recovered from COVID-19 and were discharged. The participants were followed up after 30 and 90 days.

RESULTS

At the time of enrollment, there were 602 (60.2%) males and 398 (39.8%) females. The most common neurological symptom on 30-day follow-up was headache (8.8%), followed by insomnia. The most common neurological symptom on day 90 follow-up was insomnia (5.07%), followed by an altered sense of smell (3.3%).

CONCLUSION

COVID-19 tends to produce a wide range of neurological symptoms, ranging from headache to anosmia to increased risk of stroke, that complicates clinical management. Potential neurologic effects and drug interactions have been reported secondary to the medications used to treat COVID-19. In light of the aforementioned facts, COVID-19 could potentially have a long-term effect on the brain. Therefore, it is important that the clinicians must be aware of the potential neurologic complications. Lastly, proper follow-up is recommended that would aid in timely recognition and management of the neurological disorder.

Smell and Taste Loss Recovery Time in COVID-19 Patients and Disease Severity

A significant proportion of people infected with SARS-CoV-2 report a new onset of smell or taste loss. The duration of the chemosensory impairment and predictive factors of recovery are still unclear. We aimed to investigate the prevalence, temporal course and recovery predictors in patients who suffered from varying disease severity. Consecutive adult patients diagnosed to be infected with SARS-CoV-2 via reverse-transcription–polymerase chain reaction (RT-PCR) at two coronavirus disease-2019 (COVID-19) Reference Hospitals were contacted to complete a survey reporting chemosensory loss, severity, timing and duration, nasal symptoms, smoking, allergic rhinitis, chronic rhinosinusitis, comorbidities and COVID-19 severity. In a cross-sectional study, we contacted 182 patients and 150 responded. Excluding the critically ill patients, 38% reported gustatory and 41% olfactory impairment (74% severe/anosmia). Most of the patients (88%) recovered their sense of smell by two months (median: 11.5 days; IQR: 13.3). For 23%, the olfactory loss lasted longer than a month. There were no significant differences in the prevalence and duration of chemosensory loss between groups of varying COVID-19 severity, and sexes (all p > 0.05). Moderate hyposmia resolved quicker than more severe loss (p = 0.04). Smell and taste loss are highly prevalent in COVID-19. Most patients recover fast, but nearly one out of ten have not recovered in two months.

Headache: A striking prodromal and persistent symptom, predictive of COVID-19 clinical evolution

OBJECTIVE

To define headache characteristics and evolution in relation to COVID-19 and its inflammatory response.

METHODS

This is a prospective study, comparing clinical data and inflammatory biomarkers of COVID-19 patients with and without headache, recruited at the Emergency Room. We compared baseline with 6-week follow-up to evaluate disease evolution.

RESULTS

Of 130 patients, 74.6% (97/130) had headache. In all, 24.7% (24/97) of patients had severe pain with migraine-like features. Patients with headache had more anosmia/ageusia (54.6% vs. 18.2%; p < 0.0001). Clinical duration of COVID-19 was shorter in the headache group (23.9 ± 11.6 vs. 31.2 ± 12.0 days; p = 0.028). In the headache group, IL-6 levels were lower at the ER (22.9 (57.5) vs. 57.0 (78.6) pg/mL; p = 0.036) and more stable during hospitalisation. After 6 weeks, of 74 followed-up patients with headache, 37.8% (28/74) had ongoing headache. Of these, 50% (14/28) had no previous headache history. Headache was the prodromal symptom of COVID-19 in 21.4% (6/28) of patients with persistent headache (p = 0.010).

CONCLUSIONS

Headache associated with COVID-19 is a frequent symptom, predictive of a shorter COVID-19 clinical course. Disabling headache can persist after COVID-19 resolution. Pathophysiologically, its migraine-like features may reflect an activation of the trigeminovascular system by inflammation or direct involvement of SARS-CoV-2, a hypothesis supported by concomitant anosmia.

Sudden onset, acute loss of taste and smell in coronavirus disease 2019 (COVID-19): a systematic review

BACKGROUND

Early detection, isolation and management of COVID-19 are crucial to contain the current pandemic. US Centers for Disease Control and Prevention (CDC) recently included 'sudden loss of taste (dysgeusia/ageusia) and smell (anosmia/hyposmia)' as symptoms of COVID-19. If indeed these symptoms are reliable and specific forerunner symptoms of COVID-19, then it may facilitate detection and containment of the disease. Hence, we systematically evaluated the contemporary evidence on dysgeusia and anosmia as trigger prodromal symptoms, and their prevalence in COVID-19 patients.

METHODS

Ovid MEDLINE, EBSCO host and Web of Science databases were searched between 25 December 2019 and 30 May 2020.

RESULTS

Of the 13 identified records, eight studies, totalling 11,054 COVID-19 patients, were included, as per the selection criteria. Eligible articles reflected research conducted mostly in the European community, as well as China, the US and Iran. In total, anosmia and dysgeusia symptoms were present in 74.9% and 81.3% ambulatory as well as hospitalized, mild-to-severe cases of COVID-19 patients, respectively. The European, US and Iran data indicate olfactory and gustatory symptoms appear prior to general COVID-19 symptoms in 64.5% and 54.0% of the patients, respectively.

CONCLUSIONS

To our knowledge, this is the first systematic review analysing the meager data based on the prevalence of chemosensory dysfunction in COVID-19. Critical analysis of such macro-data, as and when available, is essential to evaluate their utility as harbingers of COVID-19 onset, and to establish clinical practice guidelines both in dentistry and medicine.

Use of Google Trends to investigate loss-of-smell-related searches during the COVID-19 outbreak

BACKGROUND

Initial reports describing coronavirus 2019 (COVID-19) were dominated by the presence of cough, breathlessness, and fever; anecdotal reports suggested anosmia may also be a manifestation. We used Google Trends (GT) to investigate whether there was a surge in individuals searching for information related to smell loss during the COVID-19 epidemic in Italy, Spain, the United Kingdom, the United States, Germany, France, Iran, and The Netherlands.

METHODS

GT was used to explore internet activity related to loss of smell in the 8 aforementioned countries. Spearman rank analysis was performed to correlate loss-of-smell-relative search volumes (RSVs), with the increases of daily confirmed cases of COVID-19 and deaths attributed to disease. As a control event, we also performed analysis of smell-related searches during the last UK influenza epidemic of 2009.

RESULTS

In all 8 countries, we observed strong correlations between daily RSVs related to loss of smell, increases of daily COVID-19⁺ cases and deaths ranging from 0.633 to 0.952. All correlations were statistically significant (p < 0.05).

CONCLUSION

There is a strong correlation between the frequency of searches for smell-related information and the onset of COVID-19 infection in Italy, Spain, UK, USA, Germany, France, Iran, and The Netherlands. We hypothesize this may relate to a previously underrecognized symptom.

Anosmia and Ageusia as the Only Indicators of Coronavirus Disease 2019 (COVID-19)

The patient is a 60-year-old woman with a history of vertigo and seasonal allergies who presented to the hospital with the chief complaint of headache. Radiological findings were negative for intracranial abnormalities. The headache was due to trigeminal neuralgia. She had concurrent complaints of anosmia and ageusia without fever, respiratory symptoms, or obvious risk factors. However, it was determined to test the patient for coronavirus disease 2019 (COVID-19) infection despite extremely low clinical suspicion. Unfortunately, she was found to be COVID-19 positive after she was discharged from the hospital while she remained asymptomatic. There is currently a lack of published case reports describing COVID-19 patients with the sole symptoms of anosmia and ageusia in the United States of America.

The clinical course of smell and taste loss in COVID-19 hospitalized patients

BACKGROUND

Recent studies have demonstrated an association between a new onset of smell or taste loss and COVID-19. We investigated the prevalence of smell and/or taste loss and the clinical characteristics and recovery in a comprehensive cohort of consecutive patients treated by two COVID-19 reference hospitals and evaluated late persistence of hyposmia.

METHODS

A retrospective observational questionnaire study was conducted. All consecutive RT-PCR diagnosed patients who had been hospitalized in March-April 2020 in the COVID-19 care wards were contacted, excluding patients with cognitive disorders and severe deconditioning. The patients responded to a survey about the loss of smell and taste, nasal blockage, and rhinorrhea, rated the symptoms' severity from 0 to 4, and reported the recovery of smell and taste with time. Demographic and clinical characteristics were recorded.

RESULTS

We contacted 117 patients. Ninety responded to the questionnaire; 38.9 % of them reported olfactory and 36.66 % gustatory disorders during their disease. Smell loss prior to other symptoms was reported by 42.86 %, and severe hyposmia/anosmia by 74.28 % of the hyposmic. Among the non-ICU treated patients, 43.75 % reported hyposmia. Only 8.89 % had nasal blockage, and 6.66 % rhinorrhea. Most of the patients (85.71 %) recovered their sense of smell in 3-61 days (median: 17; IQR: 24), but 8.57 % had persistent hyposmia. For one out of four, the olfactory loss lasted longer than a month.

CONCLUSION

Smell and taste loss are highly prevalent and early symptoms in hospitalized COVID-19 patients. The great majority recover their smell, but nearly one out of ten have not recovered in two months.  HIPPOKRATIA 2020, 24(2): 66-71.

Factors that modulate olfactory dysfunction

The olfactory system is one of a few areas in the nervous system which is capable of regeneration throughout the life. Olfactory sensory neurons reside in the nasal cavity are continuously replenished with new neurons arising from stem cells. Some factors such as aging, neurodegenerative diseases, head trauma, brain tumor extraction and infection cause olfactory dysfunction which significantly influences physical wellbeing, quality of life, mental health, nutritional status, memory processes, identifying danger and is associated with increased mortality. Therefore, finding a treatment to improve olfactory dysfunction is needed. Recent research efforts in the field have shown some very promising new approaches to treat olfactory dysfunction. This review explores the current studies that have addressed therapeutic approaches to improve olfactory neuron regeneration based on cell transplantation therapy, modulation of physiological olfactory dysfunction and drug treatments.

Correlation between olfactory severity ratings based on olfactory function test scores and self-reported severity rating of olfactory loss

CONCLUSION

Olfactory test scores are significantly correlated with self-rated severity scales. However, the statistical rating based on olfactory tests did not strongly agree with the self-reported severity rating. This suggests that there is a discrepancy between olfactory test results and the severity described by patients themselves.

OBJECTIVES

This study aimed to identify the correlation between statistical ratings based on test scores and self-rating of the severity of olfactory loss.

METHOD

A total of 1555 subjects were asked to rate olfactory loss severity by one of five scales. Olfactory tests consist of the butanol threshold test (BTT) and cross-cultural smell identification test (CCSIT).

RESULTS

There were significant correlations between BTT scores and self-rated severity scales (r = 0.619, p < 0.001) and between CCSIT scores and self-rated severity scales (r = 0.597, p < 0.001) after adjustment for age, sex, and medical conditions. Using discriminant analysis for both BTT and CCSIT, scores 0-4 could be statistically rated as anosmia, scores 5 and 6 as severe hyposmia, scores 7 and 8 as moderate hyposmia, and scores 9-12 as normosmia (Wilks's lambda = 0.605, p < 0.001 for BTT and Wilks's lambda = 0.597, p < 0.001 for CCSIT).

Allergic rhinitis causes loss of smell in children: The OLFAPEDRIAL study

BACKGROUND

The objective of the OLFAPEDRIAL study was to assess the olfactory dysfunction in allergic paediatric population, which has been scarcely studied.

METHODS

Observational, cross-sectional and multicentre study evaluated the sense of smell in untreated allergic rhinitis (AR) paediatric patients aged 6-12 years.

RESULTS

Forty-four per cent (551 of 1260) of children with AR reported smell dysfunction, with both loss of smell frequency (52.1%, p < 0.001) and intensity (0.75 ± 0.84, p < 0.0001) being more frequent in patients with persistent than intermittent AR (38.0% and 0.51 ± 0.73, respectively). In addition, both loss of smell frequency and intensity increased according to disease severity (m-ARIA classification) but always being significantly higher in persistent (p < 0.0001) than in intermittent AR.

CONCLUSIONS

Children with allergic rhinitis present a mild-moderate loss of smell frequency and intensity which is clearly related to the disease duration and severity. The loss of smell can be considered, as in adults, a clinical marker of disease severity.

Oral plus nasal corticosteroids improve smell, nasal congestion, and inflammation in sino-nasal polyposis

OBJECTIVES/HYPOTHESIS

To assess the effect of oral plus intranasal corticosteroids on subjective outcomes (smell and nasal congestion) and objective outcomes (tissue eosinophilia and nitric oxide) in severe nasal polyposis (NP).

STUDY DESIGN

After a 4-week steroid washout period (w0), severe NP were randomized into a treatment group (n = 67) that receive oral prednisone for 2 weeks (w2) plus intranasal budesonide for 12 weeks (w12), and a control group (n = 22) that received no steroid treatment.

METHODS

Barcelona Smell Test 24 (BAST-24), nasal congestion, tissue eosinophilia, and nasal nitric oxide (nNO) were assessed.

RESULTS

Before treatment, patients showed a significant impairment of smell detection (30.7 ± 39.5%), identification (7.1 ± 16.1%), and forced choice (13.8 ± 23.3%) in BAST-24 compared to healthy population. At w2, the treatment group showed a significant improvement in detection, identification, and forced choice. Positive effect was also seen after 12 weeks of intranasal corticosteroids. A significant reduction of nasal congestion (1.17 ± 1.0 vs. 2.73 ± 0.5) and polyp tissue eosinophilia (10.9 ± 4.2 vs. 41.2 ± 12.2) with an increase of nNO (650 ± 317 vs. 420 ± 221 ppb) were observed at w2 compared to w0 and to the control group. These effects were also seen at w12.

CONCLUSIONS

Combined oral and intranasal corticosteroids improve smell and nasal congestion and decrease nasal inflammation, as measured by reduced tissue eosinophilia and increased detection of nNO. Severity of smell loss correlates with degree of nasal congestion but not with inflammation, as measured by tissue eosinophilia or nasally exhaled nNO. Our findings suggest that improvement in smell may be related to improved conduction of odorants to the olfactory neuroepithelium.